Neuroplasticity After Brain Injury Flashcards
What occurs in stage 1 of recovery?
- Acute and immediate recovery of local damaged brain tissue.
- Enhanced neuroplasticity: activation of learning networks which are usually active only during development to facilitate learning.
- Early recruitment of contralesional homologous brain regions or areas around the lesion to compensate for lost functions.
- Upregulation of proteins involved in neural growth and guidance, many of which mimic the neural environment.
How long does spontaneous recovery occur?
3 months after a stroke, to 6 months (in a TBI).
How long does the upregulation of proteins occur?
Relatively narrow time window after injury.
What does the mouse article summarize?
The article is basically saying that plasticity helps to restore function, however, a lot of it has to do with the compensation by other brain areas, not necessarily the original brain area. The plasticity that occurs spontaneously may largely reflect the development of compensatory motor patterns, rather than the true recovery of original kinematic patterns.
What happens if you do not do any additional training and therapy?
Compensation does not equal recovery. No additional training will promote compensation but NOT recovery.
How can plasticity have a negative effect?
Plasticity can cause the other areas to take over, and true recovery may be masked or hindered. Essentially, early contralateral homologous region recruitment may be compensatory is beneficial however, it may become inadequate since it comes with the recovering network.
What happens if plasticity takes over?
Individuals may learn non-use due to a failure to associate the brain region during acute and subacute recovery.
Why is therapy important?
Therapy will help the individual learn to use the affected area, to prevent the non-affected area from fully taking over.
What occurs in stage 2 recovery?
Training: helps to induce plastic changes in the brain to promote longer-term improvement.
After creating a great quantity of new synaptic connections, the brain shifts from quantity to quality.
Essentially, a shift to less flexibility, and more specificity, efficiency, and stability of the new structures (through experience and training, network learning/re-learning, pruning, and myelination).
Explain the activation shifts that occur during rehabilitation?
Initially, the contralesional homologous brain regions take over (skater falls, and hops on the back of the other skater).
Activation of learning structures (constraint-induced movement therapy). The skater who fell continues to skate with guidance from the other skater.
Ipsilesional distributed pattern, with a shift to a more normal pattern. The skater that fell, will learn to skate independently.
What is the purpose of rehabilitation?
The idea of rehabilitation is not to replace but to support the damaged system in relearning and restoring effective functional capacity.
What is successful functional recovery accompanied with?
New, novel patterns of activation. After a brain injury, the systems affected will likely be changed slightly, and will not function exactly how they did before.
How come plasticity can be a “double-edged sword”?
During the critical period, there is a lot of plasticity. As we continue to age, plasticity decreases and our brain stabilizes. During adulthood, plasticity continues but it is tightly regulated by cellular and molecular processes.
Disorders can disrupt the stability of the brain and can either increase or decrease plasticity above or below what is expected of “normal” aging and maturation.
Disorders like bipolar disorder can increase the likelihood of maladaptive plastic changes to take place.
How does neurotherapeutics work?
By targetting the various regulators of plasticity, the goal of neurotherapeutics is to utilize the brain’s innate capacity to change in order to improve learning, memory, and enhance recovery from neurological disease.
What kind of interventions target regulators of neuroplasticity?
Neuropharmacetucicals, cognitive training, physical exercise, and an enriched environment.
What are the limitations of plasticity and rehabilitation?
- Cortical plasticity seems to be possible only if subcortical connectivity is preserved. Studies in both stroke and TBI suggest that extensive white matter damage may result in severe permanent deficits.
- Spontaneous plasticity with no directed training may have negative consequences resulting from maladaptive changes.
- The unknown –revealing the molecular mechanisms behind the recovery cascade is crucial for optimizing timing and dose of training to leverage and not hamper the neuroplasticity boost that follows brain injury.
